Polyethylene thickened grease containing amides



United States Patent Office Patented Nov. 10, 1970 3,539,512 POLYETHYLENE THICKENED GREASE CONTAINING AMIDES Raymond Rohde and Andrew E. Skeen, Bartlesville, Okla., assignors to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Nov. 25, 1968, Ser. No. 778,818 Int. Cl. C10m 5/22 US. Cl. 252-33.3 5 Claims ABSTRACT OF THE DISCLOSURE Greases exhibiting little tendency to bleed (separation of oil) are compounded from an oil, polyolefin thickener, amide compound, sulfur-nitrogen heterocyclic compounds, lead naphthenate, salts of dinonylnaphthalene sulfonate, octylated diphenylamines and lead dialkyldithiocarbamates.

This invention relates to lubricants and more particularly to bodied lubricants or greases.

A very common deficiency of lubricant greases is the tendency for oil to separate (bleed) therefrom especially if the greases are subjected to extreme temperature conditions. Excessive oil separation from lubricant greases is, of course, undesirable. For example, it is highlydesirable that greases employed as automotive chassis lubricants exhibit very little tendency to bleed oil.

Accordingly, it is a principal object of this invention to provide grease compositions which exhibit very little tendency to bleed oil.

The low oil-bleeding greases of this invention are formulated from a lubricating oil thickened with a polyolefin to the consistency of a grease. The greases contain minor amounts of certain other components, the combination of which results in a grease which exhibits a remarkably low tendency to bleed oil.

Particularly preferred greases of this invention have the following composition:

Approximate range,

Grease components: weight percent (A) Base oil 67.0-95.9 (B) Polyolefin thickener -20 (C) Amide 0.1-5 (D) Sulfur-nitrogen heterocyclic compound 05-15 (E) Lead naphthenate 1.03.0 (F) Alkali metal salt of dinonylnaphthalene sulfonate 0.5-1.0 (G) Octylated diphenylamines 0.5-1.0 (H) Lead dialkyldithiocarbamate 0.5-1.5

The base oil can be any oil of lubricating grade such as those customarily used in compounding greases. Thus, the lubricating oil base can be a mineral, vegetable or animal oil or mixtures thereof. It is preferred that at least a major amount of the lubricating base oil be mineral in origin and most preferably a refined oil having a viscosity of about 50 to 240 SUS at 210 FpLess viscous lubricating oils result in lighter greases while heavier greases can be prepared from more viscous type oils, for example an oil having a viscosity of about 70 to 240 SUS at 210 F. White mineral oil can be used to make nonstaining greases which are particularly adapted for lubricating machinery in the textile and food industries. Paraffinic oils are preferred for the preparation of greases of low graininess.

The polyolefin thickeners employed in accordance with this invention are ethylene polymers having a density at 25 C. of at least 0.940 gram per cubic centimeter. Such ethylene polymers are disclosed in US. Pat. No. 3,112,- 270 and the disclosure therein is incorporated by reference herein. The density of these polymers generally will not exceed 0.970 although more dense, for example, polymers having a density of 1.00, can be used. The ethylene polymers which are employed include not only the homopolymer, polyethylene, but also copolymers of ethylene with olefins of higher molecular weight, for example up to 8 carbon atoms per molecule, preferably containing no branching nearer the double bond than the 4-position. Examples of suitable cornonomers include propylene, l-butene, Z-butene, l-pentene, l-octene, 4- methyl-l-pentene, 4-ethyl-l-pentene, 4-methyl-1-hexene, 6-methyl-l-heptene, 4-ethyl-1-hexene and the like. The copolymers of ethylene with propylene or l-butene are preferred and it is preferred that the polymers of ethylene be employed in fluff form. In general, ethylene makes up at least 95 weight percent of the copolymer. In forming such a polymer the monomer feed to the polymerization zone will ordinarily be at least percent by weight ethylene. As the percent of ethylene in the copolymer is decreased the density of the polymer likewise is decreased so that the density limitation can be used as an indication of copolymer composition. In any event, the density of the copolymer or homopolymer employed will be at least 0.940. The amount of polymer employed to thicken the lubricating oil to produce the desired greases will depend upon the specific oil and polymer used and upon the desired hardness of the grease. Most often, the polymer concentration in the finished grease will be in the range of 7-15 weight percent.

The amide component (C) is an N-substituted-y-hydrocarboxylic acid amide or mixtures of such amides. These additives can be represented by the general formula:

wherein R represents either hydrogen or a methyl group, R represents an aliphatic hydrocarbon radical (saturated or unsaturated) containing from 10 to 30 carbon atoms, for example, decyl, undecyl, undecylenyl, dodecyl, tridecyl, tetradecyl, cetyl, myristolenyl, pentadecyl, heptadecyl, hexadecenyl, octadecyl, octadecenyl, octadecadienyl, abietinyl, oleyl, elaidyl, octylbenzyl, eicosyl, triacontyl, and the like and combinations of such radicals; and wherein R represents either hydrogen or alkyl group of from 1 to about 18 carbon atoms, for example, methyl, propyl, butyl, amyl, hexyl, nonyl, decyl, dodecyl, cetyl, octadecyl, and the like; and wherein the total number of carbon atoms constituting the groups in both R and R is a minimum of 10 and not more than about 40 carbon atoms.

The compounds characterized by the above formula and utilized in accordance with the present invention can be obtained by conventional methods such as the reaction of one mole of an organic primary amine, or mixtures of such amines, containing from 10 to about 30 carbon atoms with one mole of either gamma-butyrolactone o'r gamma-valerolactone at a temperature of about 80-95 C. The amines have the formula R1CI{2NH2 or CH-NHZ wherein R and R have the values indicated above. Prefera bly, both R and R are hydrogen and R is formed from a mixture of saturated or unsaturated amine residues derived from naturally occurring fatty acids (by replacing the carboxyl group with a primary amino-group) such as are obtained from coconut oil, soya oil, tallow, and the like which are commercially available (for example, under the brand name of Duorneens).

Grease component D is a 2-mercaptobenzothiazole compound, an anti-rust agent conforming to the formula wherein R is selected from hydrogen or from alkyl, aryl, or cycloalkyl radicals, or combinations of these such as aralkyl, or alkaryl, containing from 1 to about 12 carbon atoms per radical, and wherein the total of all the carbon atoms in all of the R radicals in the molecule will not exceed about 20. Some examples of suitable R groups are methyl, ethyl, propyl, isobutyl, benzyl, phenyl, cyclohexyl, dodecyl, paratolyl, 2-ethylhexyl, and the like, and mixtures thereof. R is preferably hydrogen.

Although the above-described substituted and unsubstituted Z-mercaptobenzothiazole compounds can be used, it is sometimes preferred that they be utilized in the form of their amine salts. Consequently, the above mercapto compounds can be combined with an equivalent Weight of a primary, secondary, or tertiary amine compound. Such amine compounds can be monoamines or polyamines and can contain from about 2 to about 30 carbon atoms per molecule, preferably from about to about 24 carbon atoms per molecule. The preferred amines are those obtained from naturally occurring materials such as long chain organic acids derived from soya oil, coconut oil, tallow, and the like. Such fatty amines are commercially available (for example, under the brand name of Duomeens) and are prepared by conventional methods. The amine salt of the above mercapto compound is conventionally prepared merely by reacting equivalent quantities of these materials generally at elevated temperatures.

Component E is lead naphthenate. This is a commercially available material which is a derivative of naphthenic acids which are, in turn, derived from petroleum. This component imparts desirable extreme pressure properties to the composition. It is believed that these acids are produced in part by oxidation of certain readily oxidized cycloparaflins (naphthenes) during distillation or other petroleum-refining operations. Such acids dissolve in the aqueous caustic solutions used in refining. Lead naphthenate is produced merely by the addition of a lead salt to the aqueous sodium naphthenate solution. Thus, while the acid portion of these ingredients is a complex mixture, such a material, and its preparation, are Well known in the petroleum art.

Component F of the grease composition is an alkali metal salt of a dinonylnaphthalene sulfonate corresponding to the formula OuHl OaHm wherein the C H radical can be either branched or unbranched. These materials serve as anti-oxidants.

Grease component H, the inclusion of which is optional, is a lead dialkyldithiocarbamate having the formula R4 as] P. R S 2 wherein each R is a branched or unbranched alkyl radical having from 1 to about 10 carbon atoms per radical. Thus, R radicals such as methyl, ethyl, isopropyl, isobutyl, amyl, octyl, nonyl, decyl, and the like can be present.

The soapless, low-bleeding greases of the present invention are compounded, in general, by conventional methods such as those taught in Us. Pat. No. 3,112,270, Thus, the solid ethylene polymer is dispersed in the lubricating oil which has been heated to about 325 to 450 F. and generally above 380 F. for a period of time required to form a satisfactory polymer-oil dispersion. Usually, the polymer is adequately dispersed within about 1 to 60 minutes. The amide additive, as well as other conventional grease additives, is blended in with the grease during this polymer dispersion operation. The mixture is then cooled to a temperature of about 200 250 F. and the grease components D, E, F, G and H blended therein.

In addition to the polymer dispersion and additive incorporation steps, the greases are generally milled to improve their properties. In this milling operation the polymer-oil-additive dispersion described above is cooled to a temperature between about and 210 F. and subjected to severe agitation which produces substantial shearing in the mixture. Preferably the grease milling is carried out in a colloid mill operated at high speeds and with relatively close clearances. Such grease milling is conventional and known in the art.

The following are representative examples of greases prepared in accordance with this invention.

Grease A: Wt. Percent Mineral lubricating oil SUS at 210 F.) 11.50 Polyolefin thickener (density 0.95) 11.50 Reaction product of octadecylamine with 'ybutyrolactone 2.50 2-mercaptobenzothiazole 1.00 Lead naphthenate 2.00 Sodium salt of dinonylnaphthalene sulfonate 0.75 Mixture of octylated diphenylamines 0.75 Lead dipropyldithiocarbamate 0.50

Grease B:

Mineral lubricating oil (150 SUS at 210 F.) 85.0 Polyolefin thickener (density 0.94) 7.8

Reaction product of N-decylamine with 'ybutyrolactone 1 .8 2-mercapto-tetrapropylbenzothiazole 0.6 Lead naphthenate 1.5 Sodium salt of dinonylnaphthalene sulfonate 0.5 Octylated diphenylamine 1.0 Lead dioctyldithiocarbamate 1.0

Grease C:

Paraflinic lubricating oil (210 SUS at 210 F.) 76.00 Polyolefin thickener (density 0.954) 13.00 Reaction product of 0.2 mole 'y-valerolactone and 0.2 mole of a mixture of aliphatic primary amines derived from soya oil fatty acids 4.00 2-mercaptobenzothiazole 1.50 Lead naphthenate 3.00 Potassium salt of dinonylnaphthalene sulfonate 0.50 Octylated diphenylamine 0.50 Lead methylhexyldithiocarbamate 1.50

6 Grease D: additive (C) is an amide of the formula Napllstheipgc lubricating oil (95 SUS at 78 15 E 1? I Polyolefin thickener (density 0.96) 13.20 R CH2OH2CNH?H Reaction product of 86.1 grams of 'y-butyr- 5 I H olactone with 274 grams of a mixture of wherein amines: Hexadecylamine octadecyl- Rrs hydrogen or methyl, amine 10%, octadecenylamine 35%, and R is an aliphatic hydrocarbon radical containing octadecadienylamine 45% 3.20 from 10 to 30 carbon atoms, and Z-mercapto-tetrabutylbenzothiazole 1.20 10 R is hydrogen or an alkyl group of from 1 to 18 L d naphthenate 1 9 carbon atoms and wherein the total number of S di l f di l h h l carbon atoms in R and R is in the range from sulfonate 0.75 t0 octylateid QYk additive (D) is a 2-mercaptobenzothiazolecompound Lead dnsobutyldithlocarbamate 1.00 conforming to the formula The low bleeding characteristics of greases com- R pounded in accordance with the present invention are I readily apparent by the bleed test results obtained in com- R N parison with other grease compositions. Using test meth- 0 od ASTM D 1742-64, Greases E and F, (particularly pre- R /C SH ferred greases of this invention) was compared with S Greases G, H and I, which greases are not in accordance 3 with the invention. Greases E, F, G, H and I were preg i f g i g ig g g g g g i pared by first dispersing the polyethylene thickener into y y f y b m 0 r O the on by Sim l t t t f F as containing rom 1 to a out 2 carbon atoms per p e rnrxmg a a empera ure 0 After the 01 6th lane was dis rsed the amide Was in radical, and wherem the total of all the carbon atoms y y pa in all of the R radicals on the molecule will not corporated into the mixture. The mixture was then cooled exceed about 20, to a temperature of about 225 F. and the other addiddti (E) 1 d hth aw tives if any were added The mixture was then further 1? ea nap en C00 d to about 190 F A mined y p g through a additive (F) is an alkali metal salt of a dinonylnaph- I thal s lfon t rre ond'n to the formul Charlotte colloid mill. The entrained a1r was removed ene u a e co Sp 1 g a from the grease while it was hot, with the aid of a vacuum pump. Each of these greases had essentially the same 09H 09H hardness, being in the range of an NLGI Grade 2 grease. i The composition of Greases E, F, G, H and I are set forth I below: $03M Grease E, Grease F, Grease G, Grease H, Grease I wt. percent wt. percent wt. percent wt. percent wt. percent Refinedlubricating oil (110 SUS at 210 F.) derived from Mid-Continent crude. 85. Polyethylene (density -0.960, melt index -5.0) 9.0 N -eoeo-'y-hydroxybutyramide (Butoxyne 160, General Aniline and Film Corp.) 1. 0 Unsubstituted Q-mereaptobenzothiazole in the form of a salt with a high molecular weight amine (Vanlube 601, RT. Vanderbilt C0.) 1.0 Lead naphthenate 2. 0 Sodium salt of dinonylnaphthalene sulfonate 0. 5 Mixture of oetylated diphenylamlnes (Vanlube SL, R T Vanderbilt Co 0. 5 Lead diamyldithiocarbamate (Vanlube 71) 1. 0 Oil separation after 96 hours, ml 1 These data clearly illustrate the surprising results obtained from the invention Greases E and F. The combination of components in these grease formulations results in an unexpected decrease in oil bleeding. Such improved wherein M is an alkali metal and the C H radicals are either branched or un-branched radicals;

additive (G) is octylated diphenylamines corresponding to the formula results are not possible by merely incorporating a ran- H C H dom choice of any of the conventionally known grease 1 8 additives. Indeed, the addition of some commonly used grease additives substantially increases oil bleeding. The grease compositions of the present invention are valuable wherein the C H radical can be either branched or in that the greases have an excellent balance of performunbranched; ance properties in addition to the low bleeding charactive (H) i a l ad dialkyldithiocarbamate. teristic, 2. A lubricant in accordance with claim 1, wherein The Butoxyne 160 in Greases E, F and H is a product additive (C) is employed in the lubricant in an amount formed by reacting -butyrolactone with a mixture of of from 0.1 to 5% by weight, saturated and unsaturated primary amines derived from additive is mpl y in the lubricant in an amount coconut oil. of from 0.5 to 1.5 by weight,

Those modifications and equivalents which fall within additive (E) is employed in the lubricant in an amount the spirit of the invention are to be considered a part of from 1.0 to 3.0% by weight, thereof, additive (F) is employed in the lubricant in an amount We claim: of from 0.5 to 1.0% by weight, 1. A lubricant comprising a major amount of lubriadditive (G) is employed in the lubricant in an amount eating oil thickened with an ethylene polymer having a of from 0.5 to 1.0% by weight. density of at least 0.940 gram per cubic centimeter at 25 additive (H) is employed in the lubricant in an amount C. and minor effective amounts of additives (C), (D), of from 0.5 to 1.5% by weight. (E), (F), (G) and (H) wherein 3. A lubricant in accordance with claim 2 wherein additive (C) is N-coco-y-hydroxybutyramide and additive (D) is Z-mercaptobenzothiazole.

4. A thickened lubricant comprising:

about 85% by weight of a mineral lubricating oil,

about 9.0% by weight of polyethylene having a density 5 of about 0.960 gram per cubic centimeter at 25 C.,

about 1.0% by weight of N-coco-' -hydroxybutyramide,

about 1.0% by weight of a high molecular weight amine salt of 2-mercaptobenzothiazole,

about 2.0% by weight of lead naphthenate,

about 0.5 by weight of the sodium salt of dinonylnaphthalene sulfonate,

about 0.5% by weight of an octylated diphenylamine,

and

about 1.0% by weight of lead diamyldithiocarbamate.

5. A lubricant comprising a major amount of lubricating oil thickened with an ethylene polymer having a density of at least 0940 gram per cubic centimeter at 25 C. and minor effective amounts of additives (C), (D), (E), (F) and (G) wherein wherein R is selected from hydrogen or from alkyl, aryl, or cycloalkyl radicals, or combinations thereof, containing from 1 to about 12 carbon atoms per radical, and wherein the total of all the carbon atoms in all of the R radicals on the molecule will not exceed about 20;

additive (E) is lead naphthenate;

additive (:E) is an alkali metal salt of a dinonylnaphthalene sulfonate corresponding to the formula CoHm ame I $0 M wherein M is an alkali metal and the C9H19 radicals are either branched or unbranched radicals; additive (G) is octylated diphenylamines corresponding to the formula III 03H" wherein the C H radical can be either branched or unbranched.

References Cited UNITED STATES PATENTS 2,898,301 8/1959 Mayhew et al. 252-51.5 2,923,738 2/1960 Williams et a1 25251.5 2,958,665 11/1960 Stefcik et al. 252-51.5. 3,108,070 10/1963 Hartung et a1 25 2--33.3 3,112,270 11/1963 Mitacek et al. 25259 3,125,530 3/1964 Mayhew et al. 25251.5

DANIEL E. WYMAN, Primary Examiner I. VAUGHN, Assistant Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5 9 512 Dated November 10 1970 Inven r) Raymond Rohde et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 39, 195" should read (195 line 40,, "11 should read 81 .00 line 52, "85 .0" should read 85. 8 Column 6 the formula appearing at line 35 should read as follows:

SO M

Signed and sealed this 2nd day of March 1971 (SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

EDWARD M.PLETCHER,JR. Commissioner of Patents Attesting Officer FORM PO-D (10-6 USCOMM-DC cos-r 

